<!-- INVENTORY DTD -->

<!ELEMENT INVENTORY (BOOK | CD)*>

<!ELEMENT BOOK (TITLE, AUTHOR, BINDING, PAGES, PRICE, COVER?)>
<!ATTLIST BOOK category      CDATA               #IMPLIED
               instock       (yes|no)            #IMPLIED
               isbn          CDATA               #IMPLIED
               year          CDATA               #IMPLIED>

<!ELEMENT TITLE (#PCDATA | SUBTITLE)*>

<!ELEMENT SUBTITLE (#PCDATA)>

<!ELEMENT AUTHOR (#PCDATA)>
<!ATTLIST AUTHOR born         CDATA               #IMPLIED
                 died         CDATA               #IMPLIED>

<!ELEMENT BINDING (#PCDATA)>

<!ELEMENT PAGES (#PCDATA)>

<!ELEMENT PRICE (#PCDATA)>
<!ATTLIST PRICE currency     (us|gbp|rmb|eur)    "us">

<!ELEMENT COVER EMPTY>
<!ATTLIST COVER source       ENTITY              #IMPLIED>

<!ELEMENT CD (TITLE, COMPOSER?, PERFORMER+, PRICE, COVER?)>
<!ATTLIST CD category        CDATA               #IMPLIED
             instock         (yes|no)            #IMPLIED
             year            CDATA               #IMPLIED>